Pump Monitoring Using Acoustical Characterizations

ABSTRACT

An audio detection unit inside of the pump can be used to capture acoustic waveforms from the pump during operation and, when compared to characterized data, can accurately determine an operating condition of the pump. Such operating conditions can include whether the pump is operating as expected, if it has lost prime, if it has a failure, or if it can be determined that failure is likely to occur in the near future.

CROSS REFERENCE TO RELATED INFORMATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/588,060, filed Nov. 17, 2017, titled Pump MonitoringUsing Acoustical Characterizations, the contents of which are herebyincorporated herein in its entirety.

TECHNICAL FIELD

The present disclosure is directed to an apparatus and method to monitora metering pump using acoustical characterizations.

BACKGROUND OF THE INVENTION

Metering pumps are typically used to move a specified volume of liquidin a specified time to provide an accurate flow rate. Many precisionmetering pumps use a flexible diaphragm mechanism and checkballconfiguration to transfer fluid from a source tank to a process fluidtank for treatment. During a suction stroke, the diaphragm andcheckball(s) generally create a negative pressure scenario that liftsthe fluid from the source tank into the suction tube toward the suctionend of the pump. During the discharge stroke, the diaphragm andcheckball(s) generally create a positive pressure differential to movethe fluid towards the discharge end of the pump. The amount and speed offluid movement through the tubing is primarily dependent on thediaphragm displacement during each stroke cycle and the rate of cyclingthe diaphragm between suction and discharge positions. Such meteringpumps can pump chemicals, solutions, or other liquids.

Metering pumps typically require intermittent service and routinemaintenance to ensure proper operation and minimize downtime. Certainmaintenance is performed in a preventative fashion to counteractfailure, whereas other service may be required post-failure. Ideally,any service will be performed prior to failure in the field to ensureproper treatment of process fluids and effective plant operation.Accordingly, there is a need to provide an easier and more efficientmethod to detect maintenance conditions for metering pumps.

Additionally, metering pumps may experience a loss of prime condition.The initial priming sequence of the pump is the process of filling theinjection tubing with fluid. Typically, this process takes severalpumping cycles to fill the tubing adequately prior to being able toinject fluid into the process fluid tank. In some instances, diaphragmmetering pumps may be subject to a loss of prime condition where thetubing is not filled with liquid, and air or gas has built up in thecavity. During a loss of prime condition, the pressure vacuum in thetubing may be lost and the fluid may reverse flow from the tubing backinto the source tank. This may particularly occur in low duty cyclepumping applications or if the pump is turned off for an extended amountof time. When prime is lost in the system, the air can be removed andreplaced with liquid to re-prime the system through suction/dischargestrokes of the metering pump. However, this re-priming requires manualintervention, and may be time consuming and may result in under treatingthe process fluid. Accordingly, there is also a need to provide aneasier and more efficient method to detect a loss of prime condition formetering pumps.

BRIEF SUMMARY OF THE INVENTION

An audio detection unit inside of the pump can be used to captureacoustic waveforms from the pump during operation and, when compared tocharacterized data, can accurately determine if a pump is operating asexpected, if it has lost prime, if it has a failure, or if it may bedetermined that failure is likely to occur in the near future.

In one embodiment, a method of detecting an operating condition of apump may comprise detecting an acoustic waveform emitted by the pumpduring operation of the pump; determining an acoustic characteristic ofthe acoustic waveform; and comparing the acoustic characteristic with apredetermined acoustic characteristic.

Another method of detecting an operating condition of a pump maycomprise detecting an acoustic waveform of the pump during operation byan audio detection unit within the pump; determining an acousticcharacteristic of the acoustic waveform; comparing the acousticcharacteristic with a predetermined acoustic characteristic; anddetermining the operating condition of the pump based on the comparedacoustic characteristic.

A pump may comprise a mechanical drive unit comprising a drivemechanism; a liquid end comprising a diaphragm, wherein the drivemechanism is configured to translate the diaphragm; an electronic driveunit coupled with the mechanical drive unit such that the electronicdrive unit is configured to operate the mechanical drive unit; and anaudio detection unit positioned within the pump configured to detectaudible noise emitted by the pump during operation, wherein the audiodetection unit is coupled with the electronic drive unit such that theelectronic drive unit is configured to receive the detected audiblenoise from the audio detection unit.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1A depicts a schematic of a metering pump system.

FIG. 1B depicts a schematic of the metering pump system of FIG. 1A in aprimed configuration.

FIG. 2 depicts a schematic of a pump for use with the metering pumpsystem of FIG. 1A.

FIG. 3 depicts a schematic of an acoustic waveform of the pump of FIG. 2running at a normal condition.

FIG. 4 depicts a schematic of another acoustic waveform of the pump ofFIG. 2 in a loss of prime condition.

FIG. 5 depicts a schematic of another acoustic waveform of the pump ofFIG. 2 in a stalled condition.

FIG. 6 depicts a schematic of a method of operating the pump of FIG. 2based on an acoustic waveform of the pump.

FIG. 7 depicts a schematic of a display screen for displaying conditionsof the pump of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1A, an exemplary system using a metering pump isdescribed. Metering pump system (10) for pumping a specified volume ofliquid in a specified time includes a storage tank (2), a metering pump(50), and a process fluid tank (8). The metering pump (50) is fluidlycoupled with the storage tank (2) by suction tubing (4), and themetering pump (50) is fluidly coupled with the process fluid tank (8) byinjection tubing (6). Accordingly, the metering pump (50) can beoperated to pump fluid from the storage tank (2) to the process fluidtank (8), as shown in FIG. 1B, in a specified time at a desired flowrate. The initial priming sequence of the pump (50) is the process offilling the tubing (4, 6) with fluid to a primed condition shown in FIG.1B. Typically, this process takes several pumping cycles to fill thetubing (4, 6) adequately prior to being able to inject fluid into theprocess fluid tank (8). Although any type of metering pump can beincorporated into the metering pump system (10) to pump any type offluid (i.e., chemicals, solutions, water, etc.), a diaphragm meteringpump will be discussed in more detail below.

I. An Embodiment of a Pump

Referring to FIG. 2, a mechanical pump (50) for use with the meteringpump system (10) includes a mechanical drive unit (54) that can comprisea drive mechanism such as a piston or solenoid and clapper assembly. Themechanical drive unit (54) is used to move a diaphragm in a liquid end(56) to create pressure differentials in a pumping chamber whichalternately draws in fluid and expels fluid from the pumping chamber. Anelectronic drive (52), which can also be referred to as controlelectronics, both controls the operation of the mechanical drive unit(54) and include sensors to monitor the status of the pump (50). As aresult of their normal operation, mechanical pumps make audible noise(51) during operation. The current operation of the pump (50) can bedetermined based on the audible sounds it is emitting and comparing thatto historical audible patterns of the pump (50).

An audio detection unit (60) inside of the pump (50) can be used tocapture the acoustic waveforms and, when compared to characterized data,can accurately determine if a pump (50) is operating as expected, if ithas lost prime, if it has a failure, or if it may be determined thatfailure is likely to occur in the near future. The audio detection unit(60) may include, but is not limited to a microphone, a sound levelmeter, an integrating sound level meter, and a noise dosimeter. One ormore audio detection units (60) may be placed at any select one or morepositions within the pump (50). For instance, an audio detection unit(60) may be positioned near or in between any of the electronic drive(52), mechanical drive (54), and/or the diaphragm in the liquid end (56)of the pump (50). Still other suitable configurations for the audiodetection units (60) will be apparent to one with ordinary skill in theart in view of the teachings herein.

In an attempt to identify potential problems on pumps, historically amultitude of sensors would be attached to detect changes from normalbehavior. Such sensors may include thermal sensors, current meters,accelerometers, gyroscopes, etc. Acoustic detection can be as reliableas having precision sensors applied at a much lower cost, with a smallerfootprint, and not require direct coupling to monitored elements.

A. Normal Condition of the Pump

Some examples of acoustic waveforms that may be detected by the audiodetection unit (60) in the pump (50) are shown in FIGS. 3-5 forillustrative purposes. While these examples are based on data collectedfrom a solenoid-driven pump, the methodology could apply to other drivetechnologies, such as brushless DC, stepper motor, induction, etc. Forinstance, FIG. 3 shows an acoustic waveform (70) of a pump (50) runningat normal conditions. Such normal conditions may include operating thepump to sufficiently and/or accurately pump to pump fluid from thestorage tank (2) to the process fluid tank (8). This waveform (70)comprises waveform characteristics that may include, but is not limitedto, a waveform shape, a period, an amplitude, noise levels, and slope.In the illustrated embodiment, the acoustic waveform (70) comprises twoacoustic bursts for each stroke. The first acoustic burst (70 a) has ashorter amplitude, such as between about +/−0.5 decibels from areference level, and a shorter duration of time, such as about 0.05seconds. This first acoustic burst (70 a) represents the dischargestroke of the pump (50). The second acoustic burst (70 b) has a largeramplitude, such as between about +/−1 decibel from a reference level,and a longer duration of time, such as about 0.1 seconds. The secondacoustic burst (70 b) represents a good suction stroke. The electronicdrive (52) of the pump (50) may command the stroke, allowing theelectronic drive (52) to align each acoustic burst with thecorresponding commanded action. Of course, the waveform (70) can havevarying shapes, periods, amplitudes, and/or noise levels, and/or othersuitable waveform characteristics. The waveform characteristics for anacoustic waveform (70) of a pump (50) running at normal conditions mayvary based on the type of pump, selected speed, system backpressure,operating temperature, chemical viscosity, altitude of the pump (50)and/or other operating characteristics.

Such normal operating conditions of the pump (50) can be characterizedfor a selected pump (50). For instance, the pump (50) may be set to adesired pump load with the electronic drive (52) and the resultingacoustic waveform (70) of the pump (50) may be detected by the audiodetection unit (60). By monitoring the acoustic waveform (70), anyrepeatable and/or load dependent waveform characteristics can beidentified. The measured data can be stored, such as by the electronicdrive (52). The waveform characteristics can then be analyzed. Forinstance, the waveform shape, period, amplitude, noise levels and/orslope of the waveform (70) can be measured and stored to identify pumpscenarios. From the monitored waveforms, a typical acoustic waveform(70) for normal operating conditions can be determined. A sample ofpumps (50) may be used for comparison purposes to characterize a typicalwaveform (70) for a pump (50) over a select duration of time. Stillother suitable methods for determining a characterized acoustic waveform(70) for normal conditions of a pump (50) will be apparent to one withordinary skill in the art in view of the teachings herein.

B. Maintenance Condition of the Pump

In addition to varying over different operating conditions, the acousticsignature or waveform (70) of a ‘normal’ operating pump will also adjustover time as certain parts wear, friction increases, or sealsdeteriorate. Certain common maintenance items may be immediatelyrecognized based on its acoustic signature. Just as a trained automechanic can listen to an engine to pin point problems, an audiodetection unit (60) in a pump (50) can quickly identify soundsassociated with common problems. Because an audio detection unit (60)can assist in capturing the acoustic waveforms, it will be easier andmore reliable to identify subtle changes and identify problems beforethey become catastrophic as opposed to relying on a human ear ornoticing drastic changes in performance. This continues to becomeincreasingly more reliable as the number of units in the field increaseso that anomalies and characteristics across a very large sample can beused to compare behaviors. Preventative maintenance items that areidentified can then be relayed to the operator, service partner, ordistributor to ensure parts and maintenance is provided prior to failureresulting in down-time. The data captured from the install base may beuploaded to a central database and utilize data science or machinelearning to automatically identify typical pump acoustic signatures.

Utilizing known acoustic signatures or waveforms associated withfailures is one method to detect problems. Another method is detectingany deviation from a normal operating mode signature (70). A learningalgorithm can be implemented to analyze logged data from different pumpinstallations to identify the acoustic signature or waveform (70) ofnormal operation. The pump (50) can then monitor for any deviation fromthe normal signature (70) and alert the user of the potential forrequired maintenance. For instance, a weakening diaphragm of the pump(50) may become less rigid, causing the acoustic waveform of the pump(50) to have a lower amplitude on the first acoustic burst (70 a). Loosebolts can alter the acoustic signal of the pump as they vibrate orrattle, further loose bolts on the liquid end (56) can expand the fluidcavity and change the volume of fluid being pumped which might alsochange the acoustic signature as the walls for reflecting soundwaves areshifted. Bearing wear on motor-driven pumps can also be detected withacoustic signature as the rough or non-uniform surfaces worn bearingswill generate more noise than smooth bearing resulting in additionaldetectible frequencies being emitted by rotating mechanisms. Still othertypes of maintenance or pump conditions may be detected based onmonitoring the acoustic waveform of the pump (50), as will be apparentto one with ordinary skill in the art in view of the teachings herein.

If a pump acoustic waveform is trending away from normal operating modeover time in a manner that is atypical or unexpected it may beindicative that something is wrong with that particular unit. This canalert the operator, service partner, or distributor that the pump shouldbe inspected. If a problem is identified, this can be logged aspotentially exhibiting this particular acoustic signature. As futurepumps have this same problem and if they exhibit similar acousticbehaviors, this signature can be assigned to this problem. Onceassigned, this identification can be added to all pump models so that ifany pump exhibits this behavior in the future, the operator can benotified immediately of the problem and steps to resolve. Accordingly,if a maintenance condition of the pump (50) is detected based on adeviation of the acoustic waveform of the pump (50) compared to theacoustic waveform (70) of the pump (50) at normal operation, the pump(50) can be programmed to alert the user of the potential maintenancecondition and/or the pump (50) can change the operation of the pump (50)such as by reducing the speed of the pump (50) or shutting down the pump(50). Still other suitable actions may be used.

C. Loss of Prime Condition of the Pump

Because it may be desirable to maintain fluid in the tubing (4, 6) ofthe pumping system (10) such that the pump (50) is in a primedcondition, an automatic prime detection function is provided bymonitoring the acoustic characteristics of the pump (50). For instance,FIG. 4 shows an acoustic waveform (72) of a pump (50) running in a lossof prime condition. This waveform (72) comprises waveformcharacteristics that may include, but is not limited to, a waveformshape, a period, an amplitude, noise levels, and slope. In theillustrated embodiment, the acoustic waveform (72) comprises twoacoustic bursts for each stroke. The first acoustic burst (72 a)corresponding to the discharge stroke of the pump (50) has a higheramplitude than when fluid is present during normal conditions becausethere is no resistance on the discharge stroke. The second acousticburst (72 b) corresponding to the suction stroke of the pump (50) has ashorter duration of time than when fluid is present during normalconditions. Accordingly, the acoustic waveform (72) can be characterizedas a loss of prime condition of the pump (50).

If a loss of prime condition is detected, the pump (50) canautomatically re-prime the system by maximizing the stroke speed of thepump (50) for a selected amount of time. If the acoustic waveform of thepump returns to the acoustic waveform (70) corresponding to normaloperation, the pump (50) can continue normal operation. If the acousticwaveform of the pump (50) remains at the acoustic signature for a lossof prime condition, the pump (50) can alert the user of the loss ofprime condition and/or the pump (50) can change the operation of thepump (50) such as by reducing the speed of the pump (50) or shuttingdown the pump (50). Still other suitable actions may be used.

D. Stalled Condition of the Pump

An example of an acoustic waveform (74) of a pump (50) running in astalled condition is shown in FIG. 5. Accordingly, if the pump (50) isin a stalled state, meaning that the pump (50) while trying to moveliquid to the process tank out of its output port cannot overcome theback pressure exerted on the pump at the output, it will have anacoustic signature similar to the “stalled” acoustic signature shown. Astalled pump might occur due to blockage or a stuck valve or simply highback pressure in the process tank. As shown in the illustratedembodiment, the acoustic waveform (74) has only one acoustic burst (74a) per stroke. Because the discharge stroke is unable to finish, onlythe suction stroke is audible. Accordingly, the acoustic waveform (74)can be characterized as a stalled condition of the pump (50). If stalledcondition is detected, the pump (50) can alert the user of the stalledcondition and/or the pump (50) can change the operation of the pump (50)such as by reducing the speed of the pump (50) or shutting down the pump(50). Still other suitable actions may be used.

II. Operation of the Pump

By detecting that the acoustic signature of the pump (50) has deviatedfrom a normal condition, such as to a maintenance condition, a loss ofprime condition, and/or a stalled condition, it can be accuratelydetected that the pump (50) is no longer sufficiently injecting chemicalinto the process fluid (8). Referring to FIG. 6, this detection can bedetermined by detecting an acoustic waveform of the pump (50), such asby the audio detection unit (60) within the pump (50). An acousticcharacteristic of the detected acoustic waveform may then be determinedor calculated. Such an acoustic characteristic may include, but is notlimited to, a waveform shape, a period, an amplitude, an acoustic burst,noise levels, and slope. The calculated acoustic characteristic may thenbe compared with a predetermined acoustic characteristic of the pump(50). Such a predetermined acoustic characteristic may correspond to anacoustic characteristic of the pump (50) in normal operating conditions.This predetermined acoustic characteristic may be theoretical ormeasured from one or pumps (50) over a duration of time. The comparisonbetween the calculated acoustic characteristic and the predeterminedacoustic characteristic may be used to determine whether the calculatedacoustic characteristic has deviated from the predetermined acousticcharacteristic. For example, the system may be programmed to detect anychange greater than a predetermined percentage from a nominal value, orthe system may require that it remain outside a safety range for acertain period of time before identifying that it's problematic. Thesystem may also be programmed to detect a gradual change over time someasurement to measurement may be within x % but when looking at alonger time period that a problem can be identified as the acousticsignature has slowly deviated from the expected point. Other mechanismsor combinations of any of the mechanisms can also be used to determine adeviation that requires action.

This awareness by the pump (50) may alert the operator via an alarm,text message, email, or similar. The pump (50) may also attempt toself-correct the issue by entering an auto-priming mode (where the pumpincreases speed to maximum) until it detects the acoustic signature thatthe pump has returned to normal operation. Other suitable methods foroperating a pump (50) based on an acoustic characteristic of the pump(50) will be apparent to one with ordinary skill in the art in view ofthe teachings herein.

Another use for the acoustic characterization data may be to optimizethe pump efficiency. For instance, the electronic drive (52) may be usedto decrease the drive current until a stall threshold is detected asdescribed above. Using this threshold as a lower limit, the electronicdrive (52) may increase the drive current by a set margin andcontinuously monitor the acoustical nature until the electronic drive(52) detects that the pump (50) is operating reliably. This may allowthe pump (50) to operate more efficiently by using only a sufficientamount of power required to drive the pump (50) and dynamically adapt tochanging system backpressure, operating temperature, and/or chemicalviscosity.

In some instances, a backpressure estimation can be calculated based onthe amount of time needed to discharge the fluid and the drive currentneeded to overcome the system backpressure. Accordingly, the amount oftime needed to discharge the fluid can be determined by the electronicdrive (52) from the acoustic waveform detected by the audio detectionunit (60) by calculating the duration of the first acoustic burst of thepump (50). The backpressure estimation can then be displayed on the pumpscreen (80), as shown in FIG. 7. The backpressure estimation can also beused to adjust the estimated flow rate of the pump (50), which is afunction of backpressure. A backpressure calibration can be performed bythe user or in the factory to run the pump (50) at two differentbackpressures. The pump output can thereby be dynamically adjusted tospeed up the pump (50) in high pressure situations to maintain theuser-selected flow rate.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A method of detecting an operating condition of apump comprising: detecting an acoustic waveform emitted by the pumpduring operation of the pump; comparing the acoustic waveform with asignature waveform, the signature waveform representing normaloperation; and generating an alert when the acoustic waveform deviatesfrom the signature waveform.
 2. The method of claim 1, wherein theacoustic waveform is detected by an audio detection unit inside of thepump.
 3. The method of claim 1, wherein comparing the acoustic waveformcomprising comparing one or more acoustic characteristics of theacoustic waveform, the one or more acoustic characteristics includingone or more of an acoustic burst, an amplitude, a duration, a shape, anda period of the acoustic waveform.
 4. The method of claim 3, wherein thepredetermined acoustic characteristic is based on an acousticcharacteristic determined from an acoustic waveform of the pumpoperating in a normal condition over a select duration of time.
 5. Themethod of claim 1, further comprising sending the alert to a user. 6.The method of claim 1, further comprising adjusting the operation of thepump if the acoustic waveform deviates from the signature waveform. 7.The method of claim 1, further comprising determining a maintenancecondition of the pump when the acoustic waveform deviates from thesignature waveform.
 8. The method of claim 1, further comprisingdetermining a loss of prime condition when the acoustic waveformdeviates from the signature waveform.
 9. The method of claim 8, furthercomprising increasing a stroke speed of the pump for a select amount oftime when the loss of prime condition is determined.
 10. The method ofclaim 1, further comprising determining a stalled condition when theacoustic waveform deviates from the signature waveform.
 11. A method ofdetecting an operating condition of a pump comprising: detecting anacoustic waveform of the pump during operation by an audio detectionunit within the pump; determining an acoustic characteristic of theacoustic waveform; comparing the acoustic characteristic with apredetermined acoustic characteristic; and determining the operatingcondition of the pump based on the compared acoustic characteristic. 12.A pump comprising: a mechanical drive unit comprising a drive mechanism;a liquid end comprising a diaphragm, wherein the drive mechanism isconfigured to translate the diaphragm; an electronic drive unit coupledwith the mechanical drive unit such that the electronic drive unit isconfigured to operate the mechanical drive unit; and an audio detectionunit positioned within the pump configured to detect audible noiseemitted by the pump during operation, wherein the audio detection unitis coupled with the electronic drive unit such that the electronic driveunit is configured to receive the detected audible noise from the audiodetection unit.
 13. The pump of claim 12, wherein the audio detectionunit comprises a microphone.
 14. The pump of claim 12, wherein the audiodetection unit is positioned near a select one or both of the liquid endand the mechanical drive unit.
 15. The pump of claim 12, wherein thedetected audible noise comprises an acoustic waveform.
 16. The pump ofclaim 15, wherein the electronic drive unit is operable to compare theacoustic waveform with a characterized acoustic waveform.
 17. The pumpof claim 16, wherein the electronic drive is operable to determine anoperating condition of the pump.
 18. The pump of claim 17, wherein theoperating condition comprises a select one or more of a normalcondition, a loss of prime condition, a maintenance condition, and astalled condition.
 19. The pump of claim 17, wherein the electronicdrive is operable to alert a user of the determined operating condition.20. The pump of claim 17, wherein the electronic drive is operable toadjust the drive mechanism based on the determined operating condition.